winsup/cygwin/lib/_cygwin_crt0_common.cc

   1 /* _cygwin_crt0_common.cc: common crt0 function for cygwin crt0's.
   2
   3 This file is part of Cygwin.
   4
   5 This software is a copyrighted work licensed under the terms of the
   6 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   7 details. */
   8
   9 #include "winsup.h"
  10 #include "crt0.h"
  11 #include "cygwin-cxx.h"
  12
  13 /* Weaken these declarations so the references don't pull in C++ dependencies
  14    unnecessarily.  */
  15 #define WEAK __attribute__ ((weak))
  16
  17 #define REAL_ZNWX               "__real__Znwm"
  18 #define REAL_ZNAX               "__real__Znam"
  19 #define REAL_ZNWX_NOTHROW_T     "__real__ZnwmRKSt9nothrow_t"
  20 #define REAL_ZNAX_NOTHROW_T     "__real__ZnamRKSt9nothrow_t"
  21 #define REAL_ZDLPV              _SYMSTR (__real__ZdlPv)
  22 #define REAL_ZDAPV              _SYMSTR (__real__ZdaPv)
  23 #define REAL_ZDLPV_NOTHROW_T    _SYMSTR (__real__ZdlPvRKSt9nothrow_t)
  24 #define REAL_ZDAPV_NOTHROW_T    _SYMSTR (__real__ZdaPvRKSt9nothrow_t)
  25
  26 /* Use asm names to bypass the --wrap that is being applied to redirect all other
  27    references to these operators toward the redirectors in the Cygwin DLL; this
  28    way we can record what definitions were visible at final link time but still
  29    send all calls to the redirectors.  */
  30 extern WEAK void *operator new(std::size_t sz) noexcept (false)
  31                         __asm__ (REAL_ZNWX);
  32 extern WEAK void *operator new[](std::size_t sz) noexcept (false)
  33                         __asm__ (REAL_ZNAX);
  34 extern WEAK void operator delete(void *p) noexcept (true)
  35                         __asm__ (REAL_ZDLPV);
  36 extern WEAK void operator delete[](void *p) noexcept (true)
  37                         __asm__ (REAL_ZDAPV);
  38 extern WEAK void *operator new(std::size_t sz, const std::nothrow_t &nt) noexcept (true)
  39                         __asm__ (REAL_ZNWX_NOTHROW_T);
  40 extern WEAK void *operator new[](std::size_t sz, const std::nothrow_t &nt) noexcept (true)
  41                         __asm__ (REAL_ZNAX_NOTHROW_T);
  42 extern WEAK void operator delete(void *p, const std::nothrow_t &nt) noexcept (true)
  43                         __asm__ (REAL_ZDLPV_NOTHROW_T);
  44 extern WEAK void operator delete[](void *p, const std::nothrow_t &nt) noexcept (true)
  45                         __asm__ (REAL_ZDAPV_NOTHROW_T);
  46
  47 /* Avoid an info message from linker when linking applications.  */
  48 extern __declspec(dllimport) struct _reent *_impure_ptr;
  49
  50 /* Initialised in _cygwin_dll_entry. */
  51 extern int __dynamically_loaded;
  52
  53 #undef environ
  54
  55 extern "C"
  56 {
  57 int _fmode;
  58
  59 extern char __RUNTIME_PSEUDO_RELOC_LIST__;
  60 extern char __RUNTIME_PSEUDO_RELOC_LIST_END__;
  61 extern char __image_base__;
  62 #define _image_base__ __image_base__
  63
  64 struct per_process_cxx_malloc __cygwin_cxx_malloc =
  65 {
  66   &(operator new), &(operator new[]),
  67   &(operator delete), &(operator delete[]),
  68   &(operator new), &(operator new[]),
  69   &(operator delete), &(operator delete[])
  70 };
  71
  72 /* Set up pointers to various pieces so the dll can then use them,
  73    and then jump to the dll.  */
  74
  75 int
  76 _cygwin_crt0_common (MainFunc f, per_process *u)
  77 {
  78   per_process *newu = (per_process *) cygwin_internal (CW_USER_DATA);
  79   bool uwasnull;
  80
  81   /* u is non-NULL if we are in a DLL, and NULL in the main exe.
  82      newu is the Cygwin DLL's internal per_process and never NULL.  */
  83   if (u != NULL)
  84     uwasnull = false;   /* Caller allocated space for per_process structure.  */
  85   else
  86     {
  87       u = newu;         /* Using DLL built-in per_process.  */
  88       uwasnull = true;  /* Remember for later.  */
  89     }
  90
  91   /* The version numbers are the main source of compatibility checking.
  92      As a backup to them, we use the size of the per_process struct.  */
  93   u->magic_biscuit = sizeof (per_process);
  94
  95   /* cygwin.dll version number in effect at the time the app was created.  */
  96   u->dll_major = CYGWIN_VERSION_DLL_MAJOR;
  97   u->dll_minor = CYGWIN_VERSION_DLL_MINOR;
  98   u->api_major = CYGWIN_VERSION_API_MAJOR;
  99   u->api_minor = CYGWIN_VERSION_API_MINOR;
 100
 101   u->ctors = &__CTOR_LIST__;
 102   u->dtors = &__DTOR_LIST__;
 103   if (uwasnull)
 104     _impure_ptr = u->impure_ptr;        /* Use field initialized in newer DLLs. */
 105   else
 106     u->impure_ptr_ptr = &_impure_ptr;   /* Older DLLs need this. */
 107
 108   u->main = f;
 109
 110   /* These functions are executed prior to main.  They are just stubs unless the
 111      user overrides them. */
 112   u->premain[0] = cygwin_premain0;
 113   u->premain[1] = cygwin_premain1;
 114   u->premain[2] = cygwin_premain2;
 115   u->premain[3] = cygwin_premain3;
 116   u->fmode_ptr = &_fmode;
 117
 118   /* Unused */
 119   u->initial_sp = NULL;
 120
 121   /* Remember whatever the user linked his application with - or
 122      point to entries in the dll.  */
 123   u->malloc = &malloc;
 124   u->free = &free;
 125   u->realloc = &realloc;
 126   u->calloc = &calloc;
 127   u->posix_memalign = &posix_memalign;
 128
 129   /* Likewise for the C++ memory operators, if any, but not if we
 130      were dlopen()'d, as we might get dlclose()'d and that would
 131      leave stale function pointers behind.    */
 132   if (newu && newu->cxx_malloc && !__dynamically_loaded)
 133     {
 134       /* Inherit what we don't override.  */
 135 #define CONDITIONALLY_OVERRIDE(MEMBER) \
 136       if (!__cygwin_cxx_malloc.MEMBER) \
 137         __cygwin_cxx_malloc.MEMBER = newu->cxx_malloc->MEMBER;
 138       CONDITIONALLY_OVERRIDE(oper_new);
 139       CONDITIONALLY_OVERRIDE(oper_new__);
 140       CONDITIONALLY_OVERRIDE(oper_delete);
 141       CONDITIONALLY_OVERRIDE(oper_delete__);
 142       CONDITIONALLY_OVERRIDE(oper_new_nt);
 143       CONDITIONALLY_OVERRIDE(oper_new___nt);
 144       CONDITIONALLY_OVERRIDE(oper_delete_nt);
 145       CONDITIONALLY_OVERRIDE(oper_delete___nt);
 146       /* Now update the resulting set into the global redirectors.  */
 147       *newu->cxx_malloc = __cygwin_cxx_malloc;
 148     }
 149
 150   /* Setup the module handle so fork can get the path name.  */
 151   u->hmodule = GetModuleHandle (0);
 152
 153   /* variables for fork */
 154   u->data_start = &__data_start__;
 155   u->data_end = &__data_end__;
 156   u->bss_start = &__bss_start__;
 157   u->bss_end = &__bss_end__;
 158   u->pseudo_reloc_start = &__RUNTIME_PSEUDO_RELOC_LIST__;
 159   u->pseudo_reloc_end = &__RUNTIME_PSEUDO_RELOC_LIST_END__;
 160   u->image_base = &_image_base__;
 161   /* This is actually a dummy call to force the linker to load this
 162      symbol for older apps which need it. Unfortunately, ld for x86_64
 163      still emits this symbol when linking against static libs which
 164      require pseudo relocation, so we can't drop this call and the
 165      dummy function just yet. */
 166   _pei386_runtime_relocator (NULL);
 167   return 1;
 168 }
 169 } /* "C" */